Operation of servo devices for driving a motor vehicle - control, arrangement and method

ABSTRACT

A steering wheel (11) is fitted with a control (13) which, when operated in mutually independent control directions (41-45), controls the acceleration and deceleration of the vehicle, as well as upward and downward gear changing, and activates one of a number of cruise control functions. The control (13) may preferably be mounted immediately adjacent to the steering wheel rim (15) on the upper side of a wheel spoke (12), so that it may readily be operated by the driver&#39;s thumb without the necessity of releasing the grip on the wheel. Thus, the control incorporates all of the most essential driving control functions. The control according to the present invention encourages the driver to select, at an early stage, those accelerator and gear-change parameters which are most advantageous to economic driving or are most suited to the prevailing traffic conditions, the control actions required involving a minimum of manual movements. The present invention also relates to an arrangement and a method of controlling servo devices for the driving of a motor vehicle, utilizing the control (13) mounted on the steering wheel.

The present invention relates to a motor vehicle control device, avehicle control arrangement incorporating said device, and a vehiclecontrol method based on said arrangement. More specifically, the controldevice, arrangement and method are intended preferably for motorvehicles fitted with a steering wheel, in which the control device ismounted on the steering wheel such as to be accessible for manualoperation by the driver and in which the control device controls theoperation of both the accelerator and gear change functions in a simpleand safe manner to promote safe and economical driving.

STATE OF THE ART

Numerous methods of operating the accelerator, gearbox and brakes ofmotor vehicles are known. A foot pedal is the commonest means ofoperating the accelerator in a car, truck or bus powered by an internalcombustion engine, regardless of whether the engine drives the wheelsthrough a manual gearbox or automatic transmission. In some instances,this control may be augmented by means of maintaining a constant roadspeed, in the form of a `cruise control` (CC) function, usually operatedby a lever mounted on the steering column. When activated by manualoperation of the lever, the function controls the throttle in suchmanner that it strives to maintain the speed of the vehicle constant atthe value prevailing at the instant of operation. In some instances, thecruise control lever may also incorporate throttle control functions fordecelerating or accelerating the vehicle. Deceleration is achieved byabrupt closure of the throttle and acceleration by abrupt opening of thethrottle to a predetermined, constant position.

Manual accelerator controls mounted on or integral with the steeringwheel have been used in motor vehicles modified for handicapped personsmainly to meet the requirements of drivers whose legs are paralyzed.Examples of controls mounted on the steering wheel are disclosed inPatent Applications DE,A,2841786 and EP,A,-69090.

A brake control function can also be incorporated in this type ofaccelerator control in vehicles modified for handicap persons, asdisclosed in Patent Application EP,A,200769 and U.S. Pat. No. 4,496,018.

U.S. Pat. No. 4,077,487 discloses a variant with a secondary manualbrake control, mounted on the steering wheel and permitting manualoperation of the brakes.

Many of the controls devised to date have necessitated control actionsinvolving large movements, requiring the use of the complete arm orfoot, or have failed to take account of all of the control actions needto ensure that the vehicle is driven in a controlled manner.

In general, wheel-mounted brake and/or accelerator controls, as usedprimarily in vehicles modified for handicapped persons, have beeninstalled in vehicles with automatic transmissions. In this context,automatic transmissions suffer from the inherent disadvantage that agear change initiated by the driver by means of the kickdown functiontakes place only when the engine speed has increased. On the other hand,changing gear by manual operation of the gear selector lever requiresthe driver to remove his hand from the wheel.

SUMMARY OF THE INVENTION

The object of the invention is to improve and simplify the controlfunctions available to the driver, mainly those required to operate theengine and gearbox, by providing him with a readily accessible andergonomically designed control device affording control of thoseoperating systems necessary for driving the vehicle.

Combining the accelerator and gear-change controls in one and the sameunit, using different thumb grips to operate each, and mounting thecontrol on the steering wheel, affords a control system which isextremely practical for long-distance driving, and which does notrequire the driver to release his grip on the steering wheel to operatethe control, or to move one or both of his feet from pedal to pedal.

In accordance with the present invention, the control is mounted on thesteering wheel of the motor vehicle such as to be manually operable byone of the driver's fingers while the driver's hand maintains its gripon the steering wheel. A first signal generating means, responsive tomanual operation by the driver's finger, is provided for transmitting afirst control signal to a first servo device to control acceleration ofthe motor vehicle. A second signal generating means, responsive tomanual operation by the driver's finger, is provided for transmitting asecond control signal to a second servo device to initiate changing ofgears in the vehicle's transmission.

An arrangement for controlling a motor vehicle in accordance with thepresent invention includes first and second servo devices forrespectively controlling operation of the throttle and the gear box ofthe motor vehicle. An operating unit is mounted on the steering wheelsuch as to be manually operable by one of the driver's fingers while thedriver's hand maintains its grip on the steering wheel. The operatingunit includes first and second pressure sensors operable respectively inresponse to pressure from the driver's finger representing a change inacceleration to generate a first electrical signal, and in response topressure of the driver's finger representing a change of gears togenerate a second electrical signal. Control means responsive to thefirst electrical signal actuate a first servo device to controlacceleration of the engine. In response to the second electrical signal,the control means actuates the second servo device to control operationof the gear box to initiate and execute gear changes.

A method for controlling a motor vehicle in accordance with the presentinvention in which the motor vehicle includes an arrangement asdiscussed in the previous paragraph, and wherein the operating unitincludes first, second, third and fourth finger grips for generatingelectrical signals proportionate to the amount of pressure appliedthereto, includes the steps of operating the first finger grip toproduce an increase in acceleration, operating the second finger grip toproduce a decrease in acceleration, operating the third finger grip tocause upward gear changes in the gear box in a number of individualsteps and operating the fourth finger grip to produce downward gearchanges in a number of individual steps.

Mounting the control on a steering wheel spoke immediately adjacent tothe rim enables the accelerator and brake functions to be operated by asingle thumb action, using a separate and distinct thumb grip for eachfunction, without the necessity of releasing the grip on the wheel.

In one embodiment, the control incorporates an accelerator controlfunction which is proportional to the pressure applied to the controldevice. This enables the unit to be designed so that control is feasiblewithout the need for large control movements to make fine adjustments tothe throttle setting. This is an advantage in that it eliminates thenecessity of releasing the grip on the steering wheel to perform majoraccelerator adjustments, and provides the driver with direct feedbackregarding the accelerator position without taking his eyes from theroad.

The control, the system in which it is used and the method of controlemployed in this invention simplify the engine control and gear-changefacilities available to the driver. In a left-hand drive car with thecontrol mounted on the left-hand steering wheel spoke, which joins therim at the point normally gripped by the left hand, the driver canexercise complete control over the vehicle with that hand, enabling himto use his right hand, as required, to operate other functions, such asthe radio or air conditioning. Thus, the left hand may be used to gripthe steering wheel, using the thumb for complete accelerator control,exactly as provided by a conventional pedal, and for performing gearchanges.

Another object of the invention, in addition to control of theaccelerator and gear-change functions, is to enable the driver tooperate the brakes. As one suitable method, the braking control functionmay be activated when the pressure applied to the control to deceleratethe vehicle exceeds a preset value, at which the throttle is completelyclosed. The braking effort applied will be proportional to thedifferential between the preset and actual pressures.

Thus, since both accelerator control and, if applicable, brake controlfollowing closure of the throttle, will be directly related to thepressure applied by the driver, the latter will be in full control ofthese functions. Furthermore, to provide the driver with immediateconfirmation that a gear change has been effected by operation of theappropriate gear-change thumb grip in the control, the latterincorporates pressure-point devices which act on these thumb grips. Thedriver senses the pressure point directly in the finger or thumb,enabling him to repeat the operation in quick succession if several gearchanges are required.

To further enhance total driving control, the same control is used foraccelerator control up to a predetermined vehicle speed. In this case,operation of an additional thumb grip, separate from the gear-change andaccelerator thumb grips, enables the driver to select one of a number ofpreselected speeds. For convenience, the values may be preselected sothat the first represents a minimum speed limit, the second the nexthigher limit, and so on. Engagement of the appropriate preselected speedmay be performed by repeated operation of the thumb grip, preferablyagainst a pressure-point device, one operation selecting the firstvalue, two operations the second, and so on.

The invention represents a major advance in enabling a driver to controlthe vehicle manually, using a minimum of muscular effort whilemaintaining a relaxed driving posture. Comfort and safety are enhancedby the fact that the driver can quickly select the gear and throttlesetting required at any particular instant.

The invention is based on the premise that the driver is the first torealize when a gear-change or accelerator operation is required. Inaddition, it is useful to the driver, firstly, to perform gear changingbefore the need arises (as occurs frequently under criticalcircumstances, especially when overtaking) and, secondly, as driver, todecide independently on the necessity of gear changing and the degree ofaccelerator operation required. This enhances driving enjoyment andeliminates the risks inherent in driving a car with an overly automatedengine and gearbox/transmission control system, which may have anadverse effect on the driver's concentration on long-distance journeys.

The combined control which is used in this invention, and which ismounted on the steering wheel, affords a more efficient, more reliableand co-ordinated control procedure, allowing the driver to performintentional control actions by means of slight movements of the thumb ofthe hand gripping the steering wheel, unlike controls of theconventional type, which require an entire arm, or one or both legs, tobe used to perform control actions as and when necessary.

Other characteristic features and advantages are detailed in theappended claims and in the following description of one version of thecontrol according to the invention, the arrangement in which saidcontrol is incorporated, and the method whereby said arrangement is usedfor driving the vehicle. The description refers to the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a vehicle steering wheel with a control mounted on one ofthe wheel spokes for driving control purposes;

FIG. 2 is a cross-section through the control along section line II--IIshown in FIG. 1;

FIG. 3 is a partial cross-section through the control along section lineIII--III shown in FIG. 2; and

FIG. 4 shows an arrangement for controlling the accelerator, gear-changeand braking functions of the vehicle by means of a control as describedin FIGS. 1-3.

DESCRIPTION OF ONE EMBODIMENT

FIG. 1 shows one version of a control 13 according to the inventionmounted on a steering device, preferably a steering wheel 11. Thesteering wheel conventionally consists of a rim 15, which is connectedto the hub by two or more spokes 12. The hub carries a spring-loadedcover 14 which, when pressed, may activate a signal horn. The control 13is mounted on top of one spoke 12, in immediate proximity to the rim 15,enabling it (the control) to be operated, for example, by the thumbwhile the driver maintains his grip on the steering wheel rim. In theversion illustrated, the control is mounted on the left-hand spoke. Thisis advantageous in left-hand drive vehicles, in which various othercontrols, such as a gear lever, radio, air conditioning panel etc.,which require to be operated frequently with the right hand while thecar is being driven, are usually located to the right of, and at adistance from, the steering wheel 11, on an instrument panel or centreconsole. The control 13 is tiltable in four directions 41-44 in a planeparallel to the plane of the steering wheel 11. The control directionsare arranged in opposite pairs, so that in one pair 41, 42, a firstcontrol direction 41 is opposed to a second control direction 42, and inanother pair 43, 44, a third control direction 43 is opposed to a fourthcontrol direction 44, the individual pairs 41, 42 and 43, 44 beingessentially at right-angles to each other.

To permit manual operation in each of the control directions 41-44, thecontrol is provided with thumb grips 51-54, which consist of concavedepressions in the sides of a tetrahedral button 34 mounted on top ofthe upper arm 35 of the control 13. The application of pressure to thumbgrip 51 enables the control to be operated in control direction 41.Similarly, operation in directions 42-44 is achieved by applyingpressure to thumb grips 52-54 respectively.

Thus, for driving control purposes, directions 41 and 42 are usedrespectively to open and close the engine throttle, and directions 43and 44 used to change gear, upward and downward respectively, inrelation to the gear engaged at the particular instant. In one suitableversion of the control, the tetrahedral button 34 on the control 13 istruncated and is provided with a fifth thumb grip 55, consisting of aconcave depression in the truncated section and located in a planeparallel to that of the steering wheel 11. In this instance, the controlis also operable in a fifth control direction 45 (see FIGS. 2 and 3)normal to the plane of the steering wheel. Operation of thumb grip 55 incontrol direction 45 may be used to actuate a cruise control functionfor driving control purposes.

To illustrate how the control signals for each of the control directions41-45 are generated with the aid of the control 13, a basic model of thedesign is shown in FIGS. 2 and 3. In the figures, the characteristicdesign features of the device have been exaggerated in comparison withan actual control, the design of which is smaller and more compact. FIG.2 is a cross-section of the control along section line II--II in FIG. 1,through the left-hand spoke 12 of the steering wheel. Thus, foraccelerator control, the control is movable in control directions 41 and42, respectively opening and closing the throttle. A device such as astrain gauge 60, mounted on the upper arm 35 of the control, may be usedto obtain a control signal proportional to the pressure applied by thedriver to thumb grips 51 and 52. Since the lower arm 36 of control 13 islocated laterally by supporting slide bearings 37 in the recess in thewheel spoke 12 and is attached to device 63 (which will be described infurther detail below) at the bottom of the recess, the upper arm 35 willbe subjected to bending when thumb grips 51 and 52 are operated incontrol directions 41 and 42 respectively. When the control is released,the upper arm 35 will resume its original shape and the control will bereturned to the neutral position. The upper arm 35 of the control 13should preferably be manufactured from a polymer material possessing acertain flexibility, and should be of a design and size suitable for theforces required to achieve accelerator control from minimum to maximumthrottle opening, within the space provided for bending given in therecess in the wheel spoke. The upper arm 35 should preferably be ofsquare cross-section, with the strain gauge 60 attached to one of theside surfaces situated in a plane at right angles to control directions41, 42. Bending of the upper arm 35 in directions 41 and 42 will causethe strain gauge 60 to be compressed and elongated respectively,producing a signal proportional to the degree of bending and, therefore,to the pressure exerted on thumb grip 51 or 52 as appropriate.

In one alternative embodiment (not illustrated), a second strain gaugemay be attached to the opposite side of the upper arm 35 to strain gauge60. In this case, each device may be used to detect elongation only i.e.the gauges may be used to detect bending of upper arm 35 in each controldirection individually. For example, gauge 60 may be used to detectbending in control direction 42 only, while the second gauge may be usedto detect bending in control direction 41. The use of two strain gaugesalso enables the control signals from the strain gauges to be modifiedelectrically to produce a non-governing signal level when the control isin the neutral/start position, in which it must not deliver a controlsignal. Such control signal may otherwise result from the use of twoindividual gauges possessing mutually different characteristics when thecontrol is in neutral. Other alternative versions (not illustrated) mayutilise potentiometers to generate a control signal proportional to thephysical position of control 13 in control directions 41, 42, the upperarm 35 being designed to pivot in these directions in opposition toseparate spring-loaded devices. In these cases, the control, whenreleased, is returned to the neutral position with the aid of thespring-loaded devices, which thus comprise the return mechanism.

For the purpose of controlling a cruise control function, the control 13is movable in control direction 45 in opposition to a diaphragm switch63 attached, for example by bonding, to the bottom of the recess and tothe lower arm 36 of the control. The use of a conventional diaphragmswitch enables a defined pressure point to be obtained when the fifththumb grip 55 is operated in control direction 45. On passing thepressure point, the diaphragm switch operates, closing an electricalcircuit to produce a signal which is used to activate the cruise controlfunction. When the control is operated in control direction 45, theupper arm 35 and the lower arm 36 of the control are pressed downwardsagainst the diaphragm switch 63, sliding between the supporting slidebearings 37. Consequently, the tetrahedral button 34 on top of thecontrol is mounted above the upper surface of the steering wheel spoke12 by a distance slightly exceeding the amount by which the diaphragmswitch can be compressed on passing the pressure point.

The devices used for upward and downward gear changing when the controlis operated in directions 43 and 44 are illustrated in FIG. 3. The upperarm 35 of the control 13 is connected to the lower arm 36 by a pivot 38.This arrangement enables the upper arm to be tilted, firstly, in controldirection 43 (to the left in FIG. 3 and inward towards the steeringwheel hub in FIG. 1), acting on a second diaphragm switch 61 and,secondly, in control direction 44 (to the right in FIG. 3 and radiallyoutward from the wheel hub in FIG. 1), acting on a third diaphragmswitch 62. Since diaphragm switches 61 and 62 should preferably beattached only to the wall of the recess in the spoke 12, neither will besubject to a pulling force when the control is operated in the oppositecontrol direction. Diaphragm switches 61, 62 enable a defined pressurepoint to be obtained when the third and fourth thumb grips 53 and 54 areoperated in control directions 43 and 44 respectively. Diaphragm switch61 is operated when the control 13 is moved in control direction 43. Onpassing the pressure point, the diaphragm switch operates, closing anelectrical circuit to produce a signal which is used to initiate anupward gear change in relation to the gear engaged at that particularinstant. Diaphragm switch 62 is operated when the control 13 is moved incontrol direction 44. On passing the pressure point, the diaphragmswitch operates, closing an electrical circuit to produce a signal whichis used to initiate a downward gear change in relation to the gearengaged at that particular instant. To ensure that only the upper arm 35of the control turns about its pivot 38, the lower arm 36 is fixed inposition laterally by slide bearings 37.

Sensors (strain gauges and diaphragm switches) 60-63 are also connectedby signal leads 39 to a control unit, which actuates the various servosas appropriate. The leads may be run through the steering wheel 11 in anumber of different manners to a transfer device on the steering column,from whence they are connected to the control unit. The transfer devicemay consist of a number of conductor loops providing an additionallength of lead which is reeled and unreeled as the steering wheel isturned, an alternative type employing wiper contacts or an opticalsignal transfer device.

The control 13 located on the left-hand steering wheel spoke 12 andcontrol directions 41-45 may, therefore, be used to control theaccelerator and gear-change functions as follows: An increase inacceleration may be achieved by pressing thumb grip 51 upward with thethumb of the left hand. This corresponds to a movement away from a handgripping the rim of the steering wheel 15 in a natural manner beside theleft-hand spoke. An upward gear change is achieved by pressing thumbgrip 53 with the thumb in the direction of the wheel hub in a movementaway from the hand. Deceleration is effected by pressing thumb grip 52downward with the thumb in a movement towards the hand, while a downwardgear change is achieved by pressing thumb grip 54 inward towards thehand. Since the nine or ten o'clock position is the natural andrecommended position for placement of the left hand on the steeringwheel, with the right hand at two or three o'clock (twelve o'clockrepresenting the top of the wheel), control directions 41-44 affordlogical control movements, reductions being effected by pullingmovements towards the hand and increases pressure movements away fromthe hand.

The depressions formed in thumb grips 51-55 offer a natural position forthe thumb on the tetrahedral control button 34 for the purpose ofperforming operations in control directions 41-45. Since the button isalso of limited size, the control can be operated in all directionswithout requiring the driver to alter the grip of his left hand on thesteering wheel rim 15. Thus, the control can be operated by relativelysmall, simple manual adjustments performed solely with the thumb and, byvirtue of its location adjacent to the natural position of the hand,facilitates rapid control, enabling the driver to react quickly totraffic situations as they arise.

The sensors used enable the driver to sense directly through his thumbwhether the cruise control, upward gear change or downward gear changefunction has been activated by operation of thumb grips 53-55 since thepassage of the pressure point in the particular diaphragm switch canclearly be felt by the thumb. The degree of accelerator controlresulting from operation of thumb grips 51-52 can likewise be sensed bythe thumb, since this is proportional to the pressure applied. Thiseliminates the need for the driver to take his eyes from the road, sinceit is only necessary to locate the steering wheel spoke 12 with the handand feel the control button 34 with the thumb for the correct thumb gripfor the control measure contemplated at that instant.

The natural manoeuvrability of the control with the thumb also ensuresthat the operation of other control stalks (if any) on the steeringcolumn, such as direction indicator, windscreen wiper and, in somecases, lighting controls, can be operated independently. Since controlstalks of this type (which do not influence the actual driving of thevehicle) are operated naturally with the digits of the hand other thanthe thumb, the actions required to operate them are completelydifferent. This enhances driving safety, since a column-mounted drivingcontrol lever might easily be operated inadvertently instead of anotherintended control.

FIG. 4 is a schematic of an arrangement employing the control signalssupplied by the control 13, showing the system components required toimplement a control method in accordance with the present invention. Thearrangement is used in a motor vehicle equipped with an internalcombustion engine 1 and a transmission 2-5 to transmit the drive fromthe engine 1 to the drive wheels 6. The transmission consists of agearbox 2, a propeller shaft 3, a differential 4 and half shafts 5driving the drive wheels 6 which, in this instance, are represented bythe rear, unsteered wheels. Although the steered front wheels fitted tothis particular vehicle are not shown, the invention may, of course,also be applied to front-wheel drive vehicles.

The gearbox 2 may, in the conventional manner, be operated by means of aseparate gear lever 32 mounted on the center console or the steeringcolumn of the vehicle, and may also be of one of a number of differenttypes. For example, a conventional mechanical stepped gearbox, in whichthe gear lever 32 is the primary device used to control all gearchanging or selection of the lower gears only. A control according tothe present invention may be used as a secondary device to control allgear changing or selection of the higher gears only, in which case acomputer-controlled, electric or hydraulic motor may be used to engageeither fixed mechanical gears or other types of gears in an auxiliaryhydraulic gearbox coupled in series with the mechanical gearbox. Inother cases, the gearbox may be an automatic hydraulic transmissionoperated by means of a conventional selector lever 32 in a typicalP-R-N-D-2-1 configuration, position D affording automatic changingbetween first, second and third gear, but using a control according tothe present invention to correct gear selection, possibly with theaddition of a number of speeds higher than gears 1- 3. In theconventional P-R-N-D-2-1 shift configuration, P stands for PARKING, Rfor REVERSE, N for NEUTRAL, D for DRIVE (automatic forward drive), whilepositions 2 and 1 are used for permanent engagement of second and firstgear respectively. Although this configuration is used primarily inthree-speed automatic transmissions, other configurations are availablefor transmissions such as four speed automatics, in which an additionalposition, designated 3, permits permanent engagement of third gear. Someautomatic transmissions also offer alternative gear-change programmersin which an extra position D may be used to afford sportier performance,higher engine speeds at the gear engagement points, either when changingup or down, or increased engine braking. A control according to thepresent invention may, however, also be used for manual correction ofgear selection in these alternative programs.

The engine 1 of the vehicle is controlled by means of an electricallyoperated throttle (EST) 16 through a servo device 8. The latter, inturn, is controlled in conventional manner, basically by an acceleratorpedal (not shown).

The vehicle is also equipped with a brake servo 10 which controls theoperation of the front brakes 31 (not shown) and the rear brakes 30. Thebrake servo is controlled in conventional manner, basically by afootbrake pedal (not shown).

Control of the arrangement by means of a control according to thepresent invention is achieved by means of a control unit 7, whichperforms its secondary function of controlling the servo devices 8-10for the throttle 16, the gearbox 2 and the brakes 30-31 using a seriesof signal inputs supplied by a number of sensors 20-28 and manualswitching devices 17, 18. The control unit also includes a memory 19 inwhich at least one vehicle speed control setting may be stored.

All of the sensors 20-28 which supply the control unit 7 with signalsare shown in a single block in FIG. 4. Sensor 20 supplies a signalproportional to speed of the vehicle and sensor 21 a signal proportionalto the engine speed. Sensor 22 supplies a signal indicating if theordinary accelerator pedal has been operated and is not in its neutralposition, while sensor 23 fulfills the same function for the ordinarybrake pedal. Sensor 24 represents diaphragm switch 61 and sensor 25diaphragm switch 62, which supply signals indicating upward and downwardgear changes respectively as initiated by the driver by means of thecontrol 13. Sensor 26 represents strain gauge 60, which supplies asignal proportional to acceleration or deceleration, depending on thedegree of bending of the upper arm 35 of the control 13 in response tothe pressure applied to the third or fourth thumb grip 53 or 54respectively. Sensor 27 represents diaphragm switch 63, which supplies asignal when the cruise control function is activated by the driver.Sensor 28 supplies a signal describing the instantaneous angulardeviation of the steering wheel 11 from the straight-ahead neutralposition.

A clutch pedal sensor is not required since the arrangement described isa typical version of the invention employing an automatic hydraulictransmission or a fully automated mechanical stepped gearbox without aclutch.

Two manual switching devices are also used to control and modify thefunction of the control unit. One device 18 incorporates a switch 49 foractivating and deactivating the control response of the control unit tooperation of the control 13. This switch 49 may preferably be of themechanical or electrical monostable flip-flop type, which switches tothe deactivated position, for example when the vehicle ignition isswitched off, and can enter the activated mode only when operatedintentionally while the ignition remains on. A second switching device17 is used to enter different vehicle speed control settings in thecontrol unit memory 19. A control switch 40 enables the driver tomanually preselect and set different vehicle speed control settings. Thecontrol switch may be designed so that simple depression of a controlknob, followed by rotation of the knob to a position corresponding to afirst control setting and a further, final depression, will transmit andenter the setting in a first memory address 46 in the control unitmemory, through switching device 17. Rapid double depression of theknob, followed by rotation to a second control setting and a furtherfinal depression, will transmit and enter a second setting in memoryaddress 47. A third control setting may be entered in a third memoryaddress 48 by executing three rapid depressions of the knob andrepeating the rest of the foregoing procedure. The number ofprogrammable settings need be limited only by the available memorycapacity and by the number considered manageable and usable by thedriver. The first setting may be a low speed limit, such as 50 km/h, thesecond a higher speed limit, such as 70 km/h, and so on. Some form ofdisplay showing the values and sequence of the settings currently usedfor cruise control should preferably be displayed on the instrumentpanel. This display may be used primarily to indicate other engineparameters, such as fuel consumption, showing the controlled speed orthe speed setting of the cruise control system only while settings arebeing entered or for a limited period following activation of the cruisecontrol function.

The control 13 itself may be used instead of the switching device 17, 40to enter new vehicle speed control settings. This is achieved byapplying a pressure for longer than normal in control direction 45,whereupon a new value corresponding to the instantaneous speed of thevehicle will be entered. In this case, the speed control setting-first,second or third-to be altered should first be displayed by depressingcontrol 13 in control direction 45 the appropriate number of times.

The control unit 7 incorporates a function whereby the throttle servo 8,the gear-change servo 9 and the brake servo 10 are actuated onlysecondarily in response to operation of the control 13, provided alsothat certain other conditions are satisfied. A first condition is thatthe switching device 18 is switched on by activation of the switch 49while the ignition 33 is also switched on. Thus, the aforementionedcontrol unit function is automatically disconnected when the vehicle isstarted, affording the driver the option of not actuating or completelydisabling actuation of the servo devices 8-10 by the control 13.

A second condition is that the ordinary accelerator and brake pedalsmust not be operated i.e. the pedals must be in the neutral position asdetected by sensors 22 and 23. This enables the driver to immediatelydisable actuation of the servos 8-10 by the control unit in response tooperation of the control 13, for example, in an emergency trafficsituation in which it is necessary to brake heavily or acceleraterapidly with the aid of the pedals.

A third condition is that the steering wheel travel must not be suchthat the control 13 is operated inadvertently by possible movement ofthe right hand towards wheel spoke 12, which is located initially on theleft when the wheel is in the straight-ahead position. To prevent this,the position of the steering wheel 11 is detected by a steering positionsensor 28 which, on rotation of the wheel beyond a threshold positionbetween 90 and 180 degrees from the initial position, will inhibit and,if necessary, disable actuation of the servos 8-10 by the control unitin response to operation of the control 13.

A fourth condition is that the engine must be running, as detected bythe engine speed sensor 21.

A fifth condition, which may be applied for reasons of safety, mayconsist of a vehicle speed setting, for example a threshold valuebetween 20 and 40 km/h, below which the control unit 7 control functionis disabled. This prevents sudden acceleration or accidental gearchanging if the control 13 is operated inadvertently immediately onstarting or when the vehicle is being operated slowly and with extremecaution due to prevailing traffic conditions. A vehicle speed sensor 20is used to supply the control unit 7 with signals enabling it to verifythat the fifth condition has been satisfied.

Certain safety conditions can be monitored by the servo devices 8-10when these are being controlled only secondarily by the control unit 7.For example, the reception of secondary control signals from the controlunit by the gear-change servo 9 may be completely inhibited by manualengagement of a gear by means of the gear lever 32, or engagement ofreverse or positions other than D in an automatic transmission. Forfurther enhanced safety, the conditions may be verified by both thecontrol unit 7 and each of the servo devices 8-10 individually.

The control 13 actuates the servo devices 8-10 through the control unit7 in the following manner, provided that the foregoing conditions aresatisfied: if pressure is applied to thumb grip 51 of the control incontrol direction 41, sensor 26, 60 will deliver an acceleration signalproportional to the pressure. This signal is detected by the controlunit 7 and is used to actuate the accelerator servo, opening thethrottle by a corresponding amount. When the driver releases the controlafter the desired increase in speed has been achieved, the instantaneousspeed of the vehicle is automatically stored as a temporary setting in amemory in the control unit 7, which then controls the accelerator servoso as to maintain the speed of the vehicle at this value. If pressure isapplied to thumb grip 52 of the control in control direction 42, sensor26, 60 will deliver a deceleration signal proportional to the pressure.This signal is detected by the control unit 7 and is used primarily toactuate the accelerator servo, closing the throttle by a correspondingamount. However, the signal from sensor 26, 60 already corresponds tofully closed throttle in an intermediate position between the neutralposition of the control 13 and full travel in control direction 42. Thecontrol unit 7 then compares the current signal from sensor 26, 60 witha preset reference signal, corresponding to closed throttle, stored inits own memory. When the signal from sensor 26, 60 exceeds the referencevalue, the control unit 7 also actuates the brake servo 10 so that abraking force is applied to the front and rear wheels 31 and 30respectively of the vehicle. The control unit 7 controls the brake servo10 so that the braking effort applied is proportional to the signal fromsensor 26, 60 and the amount by which it exceeds the reference signal.When the driver releases the control after the desired decrease in speedhas been achieved, the instantaneous speed of the vehicle isautomatically stored as a temporary setting in a memory in the controlunit 7, which then controls the accelerator servo so as to maintain thespeed of the vehicle at this value. Cruise control using this temporarycontrol setting may be overridden temporarily when a control action suchas operation of the accelerator or brake pedal, or another gear-changeoperation by means of the control 13 or the gear lever 32, is performed,or if the engine cannot maintain the speed under the prevailing loadconditions. However, the temporary speed control setting may bereactivated if, for example, the control 13 is actuated by simpledepression in control direction 45.

The accelerator control function in the control 13 may thus be used forfine adjustment of the vehicle speed. In this context, the term `fineadjustment` signifies that the driver can adjust and maintain the speedof the vehicle after operation of the function without the necessity ofoperating the control continuously, provided that the other relevantconditions are satisfied.

One depression of thumb grip 53 on the control 13 in control direction43 will cause sensor 24, 61 to deliver a signal pulse when the pressurepoint in diaphragm switch 61 is passed, corresponding to a signalinitiating a single upward gear-change. On detecting the signal fromsensor 24, the control unit 7 actuates the gear-change servo 9 to selectthe next highest gear in relation to that engaged at the particularinstant. Two rapid depressions in control direction 43 will cause thecontrol unit 7 to actuate the gear-change servo 9 to change up twogears. In similar manner, downward gear changing is achieved by applyingpressure to thumb grip 54 of the control in control direction 44.

One depression of thumb grip 55 on the control 13 in control direction45 will cause sensor 27, 63 to deliver a signal pulse when the pressurepoint in diaphragm switch 63 is passed, corresponding to a signalinitiating cruise control at a preset speed setting. On detecting thesignal and the number of signal pulses from sensor 27, the control unit7 actuates the accelerator servo 8, using a first preset speed controlsetting to determine the servo opening when one signal pulse is detectedand a second preset setting when two signal pulses are detected. Thespeed control settings are stored in the memory 19 of the control unit7, in which they may be entered, for example, with the aid of switchingdevice 17, 40.

The control unit may consist ideally of a microprocessor designedspecifically for the purpose, including a CPU, an interface as requiredin instances in which the input/output signals are not directlycompatible with the CPU or the servos 8-10, and memories of both the ROMand RAM type. The control functions of the control unit 7 are stored inthe form of a program in a non-volatile storage memory. The programincorporates interrupt functions which enable the control conditions forthe control unit to be monitored continuously. The temporary speedsettings which are adopted automatically when the accelerator control inthe control 13 is released in control directions 41, 42 may ideally bestored in a volatile storage memory, which is erased/zeroed when theignition is switched off. The speed settings entered with the aid ofswitching device 40, 17 may preferably be stored in memories which arenot erased when the ignition is switched off. The software may alsoincorporate safety functions which inhibit the engagement of a gearwhich may cause the engine 1 to race or stall, as well as variousaccelerator control functions which may be utilised as determined by theprevailing speed of the vehicle, the gear selected and the magnitude ofthe instantaneous deviation in vehicle speed from the control settingused by the cruise control function following its activation.

The control signals supplied by the control unit 7 to the servo devices8-10 are also processed as secondary in systematic terms and cannotoverride the servo control functions as governed by the appropriateprimary controls, such as the accelerator and brake pedals or the gearlever.

In practice, the present invention may conveniently be used incombination with a conventional set-up of driving controls, finding itsmain application in long-distance driving, in which the vehicle may bedriven very easily, using a minimum of control actions, wholly inaccordance with the wishes of the driver and readily adaptable toprevailing traffic conditions.

The above description of one version of a control, arrangement andmethod of controlling the driving of a motor vehicle according to thepresent invention should not be regarded as restricting the basicconcept of the invention as disclosed in the appended Claims. Theinvention may, without infringing the spirit or scope of said Claims,instead of the tetrahedral button, employ a cluster of switches arrangedwithin a finite operating area on the steering wheel, the switches beingmounted adjacent one another and supplying, possibly without perceptiblephysical movement, corresponding control signals for the accelerator andgear-change functions, and for the activation of several cruise controlfunctions.

A rotary control designed to rotate about an axis parallel to the thirdand fourth control directions in the embodiment already described may beused as an alternative to the tetrahedral button 34. A control of thistype may take the form of a short cylinder mounted essentially withinthe steering wheel spoke, with part of the peripheral surface(preferably knurled) projecting above the upper surface of the spoke. Tocontrol acceleration, the control may rotate about its axis, in thefirst and second control directions, in opposition to spring-loadeddevices. To control the gear-change and cruise control functions, theentire control may be operable, in the third, fourth and fifth controldirections, in opposition to pressure-point generating devices. Portionsof the peripheral surface of the control may, if required, also projectbelow the underside of the wheel spoke to permit operation by digitsother than the thumb.

As an alternative to the location of the control on a spoke whichconnects the rim of the steering wheel with the hub, as proposed in theversion described, the control may be mounted on the outer end of aspoke which rotates together with the hub and extends outwards towardsthe rim, but which is not actually connected to the rim. This extraspoke may be made adjustable in different rotary and vertical positionsin relation to the plane of the rim to suit the needs of individualdrivers. Furthermore, control directions other than the configurationproposed in the version of the present invention described in theforegoing may be considered more natural, depending on the point atwhich the wheel spoke 12 is connected to the rim 15.

We claim:
 1. A control for controlling the operation of a motor vehicle,the vehicle having an engine with a throttle, an accelerator control foroperating the throttle, a transmission with a gearbox and a vehiclesteering wheel;the control having first, second and third servo devicesconnected to the control; the first servo device being connected to theaccelerator control of the vehicle; the second servo device beingconnected to the gearbox of the transmission; the third servo devicebeing for controlling the engine throttle; the steering wheel includinga rim and spokes; the control being mounted on the steering wheel of themotor vehicle on at least one of the spokes adjacent the rim, at alocation to be manually operable by the driver's fingers while thedriver's hand having the operating fingers maintains its grip on thesteering wheel; the control further comprising: first signal generatingmeans responsive to a first manual operation by the driver's finger fortransmitting a first control signal to the first servo device for theaccelerator control; second signal generating means responsive to asecond manual operation by the driver's finger for transmitting a secondcontrol signal to the second servo device to initiate and executechanging of gears in the vehicle transmission gearbox; and third signalgenerating means responsive to a third manual operation by the driver'sfinger for generating a third control signal to the third servo devicerepresentative of a speed at which it is desired to maintain the vehiclefor the throttle to be set to maintain the desired speed; a controlelement movable in response to the driver's finger in first, second,third, fourth and fifth control directions, and in which the firstsignal generating means is responsive to movement of the control elementin either of the first and second directions, the second signalgenerating means is responsive to movement of the control element ineither of the third and fourth directions, and the third signalgenerating means is responsive to movement of the control element in thefifth direction.
 2. A control according to claim 1, in which the firstand second control directions are substantially at right angles to aradius of the steering wheel.
 3. A control according to claim 2, inwhich the third and fourth control directions are substantially at rightangles to the first and second directions and substantially parallel tothe radius of the steering wheel.
 4. A control according to claim 3, inwhich the fifth control direction is substantially at right angles tothe plane of the steering wheel.
 5. A control according to claim 1, inwhich the control element is responsive to pressure from the driver'sfinger in the first and second control directions to move the controlelement from a neutral position in the first and second directions,respectively, the control element being structured and arranged such asto return to the neutral position when such pressure is removed.
 6. Acontrol according to claim 1, in which the control element is mountedfor pivoting motion in the third and fourth control directions and isresponsive to pressure from the driver's finger in the third and fourthcontrol directions to pivot away from a neutral position in the thirdand fourth directions; and in which the second signal generating meansis responsive to respective predetermined amounts of movement in thethird and fourth control directions and includes means for returning thecontrol element to its neutral position upon removal of such pressure,the control element including means for providing a sensory response tothe driver's finger when the control element has moved the respectivepredetermined amounts in the third and fourth control directions.
 7. Acontrol according to claim 1, in which the control element includes asubstantially tetrahedral button with four concave side surfaces, theopposite surfaces being arranged respectively in pairs parallel to thefirst and second control directions, and to the third and fourth controldirections so that the tetrahedral button is operable for movement inthe first, second, third and fourth directions in a plane substantiallyparallel to the plane of the steering wheel, the tetrahedral buttonfurther including a truncated top surface with a concave depression inthe fifth control direction.
 8. An arrangement for controlling a motorvehicle having an engine, drive wheels driven by the engine and agearbox installed between the engine and the drive wheels of thevehicle, the vehicle engine also including a throttle, and the vehicleincluding a steering wheel; the arrangement comprising:first and secondservo devices respectively for controlling acceleration of the engine bycontrolling operation of the throttle and for controlling the gear box;an operating unit mounted on the steering wheel at a location to bemanually operable by the driver's fingers while the driver's hand havingthe operating fingers maintains its grip on the steering wheel; theoperating unit including first and second pressure sensors, the firstpressure sensor being operable in response to pressure by the driver'sfinger representing a desired change in acceleration to generate a firstelectrical signal and the second pressure sensor being operable inresponse to pressure by the driver's finger representing a desiredchange of gears to generate a second electrical signal; and controlmeans responsive to the first electrical signal for actuating the firstservo device to control acceleration of the engine and responsive to thesecond electrical signal for actuating the second servo device tocontrol operation of the gearbox to initiate and execute gear changes; amemory unit containing a plurality of speed control settings and theoperating unit including a third pressure sensor responsive to pressurefrom the driver's finger for generating a third electrical signalrepresentative of one of the speed control settings stored in the memoryunit, the arrangement being responsive to the third electrical signaland the memory unit for actuating the first servo to maintain the speedof the vehicle at the selected speed setting.
 9. An arrangementaccording to claim 8, further including means for enabling entry of theplurality of speed control settings in the memory unit.
 10. Anarrangement according to claim 9, including means connected with thesteering wheel for disabling control of the servo devices in response torotation of the steering wheel beyond a threshold position within asector between 90° and 180° from the straight ahead position of thesteering wheel.
 11. An arrangement according to claim 10, furtherincluding means enabling the driver to manually disable the response ofthe servo devices to operation of the operating unit.
 12. A control forcontrolling the operation of a motor vehicle, the vehicle having anengine with a throttle, an accelerator control for operating thethrottle, a transmission with a gearbox and a vehicle steering wheel;thecontrol having first and second servo devices connected to the control;the first servo device being connected to the accelerator control of thevehicle; the second servo device being connected to the gearbox of thetransmission; the steering wheel including a rim and the control beingmounted on the steering wheel adjacent the rim at a location to bemanually operable by the driver's fingers while the driver's hand havingthe operating fingers maintains its grip on the steering wheel; thecontrol further comprising: first signal generating means responsive toa first manual operation by the driver's finger for transmitting a firstcontrol signal to the first servo device for the accelerator control;and second signal generating means responsive to a second manualoperation by the driver's finger for transmitting a second controlsignal to the second servo device to initiate and execute changing ofgears in the vehicle transmission gearbox; the control comprises acontrol element moveable in response to the driver's finger in first andsecond and in third and fourth control directions, the first signalgenerating means being responsive to movement of the control element ineither of the first and second directions, and the second signalgenerating means being responsive to movement of the control element ineither of the third and fourth directions.
 13. A control according toclaim 12, wherein the first and second directions are opposite eachother and the third and fourth directions are opposite each other andalso are at right angles to the first and second directions.
 14. Acontrol according to claim 12 wherein the control element is alsomovable in response to the driver's finger in a fifth controldirection;and third signal generating means responsive to a third manualoperation by the driver's finger for generating a third control signalto the third servo device representative of a speed at which it isdesired to maintain the vehicle for the throttle to be set to maintainthe desired speed; and the third signal generating means beingresponsive to movement of the control element in the fifth direction.15. A control according to claim 14, wherein the first and seconddirections are opposite each other, the third and fourth directions areopposite each other and are at right angles to the first and seconddirections, and the fifth direction is at right angles to both of thefirst and second directions and the third and fourth directions.
 16. Anarrangement for controlling a motor vehicle having an engine with athrottle, drive wheels for being driven by the engine and a gearboxinstalled between the engine and the drive wheels of the vehicle, thevehicle also including a steering wheel for steering the vehicle, thesteering wheel having a rim,the arrangement comprising: an operatingunit mounted on the steering wheel at a location to be accessible foroperation by the driver's fingers while the driver's hand having thefingers grips the steering wheel, the operating unit including first,second, third and fourth finger grips thereon each individuallyrespectively operable by the driver's fingers, means connected to eachof the finger grips for generating a respective first, second, third andfourth electrical signal proportional to the amount of pressure appliedto the respective finger grips; control means, including a first servodevice connected with the first and second finger grips for receivingthe first and second electrical signals and being connected with thethrottle for controlling engine acceleration; the connections betweenthe first and second finger grips, the first servo device and thethrottle being such that operating the first finger grip increasesacceleration of the vehicle and operating the second finger gripdecreases acceleration of the vehicle; a second servo device connectedwith the third and fourth finger grips for receiving the third andfourth electrical signals therefrom and being connected with the gearboxfor initiating and executing gear changes in the gearbox; theconnections between the third and fourth finger grips, the second servodevice and the gearbox being such that operating the third finger gripoperates the second servo device to cause an upward gear change in thegearbox while operating the fourth finger grip operates the second servodevice to cause a downward gear change in the gearbox.
 17. Thearrangement of claim 16, wherein the first servo device maintains thespeed of the vehicle at the speed it was travelling when pressure isremoved from either of the first and second finger grips.
 18. Thearrangement of claim 17, wherein the vehicle further includes a brake;the first servo device being connected with the brake for being operatedto activate the vehicle brake;the first servo device having a thresholdvalue for pressure applied to the second finger grip, such that pressureup to a threshold value applied on the second finger grip causes thefirst servo device to close the throttle while pressure applied to thesecond finger grip above the threshold value causes the first servodevice to activate the vehicle brake to a degree related to the extentto which the pressure applied to the second grip exceeds the thresholdvalue of pressure.
 19. The arrangement of claim 18, further comprising afifth finger grip on the operating unit and a third servo deviceconnected with the fifth finger grip for setting the throttle to causethe vehicle to travel at a predetermined speed setting.
 20. Thearrangement of claim 19, wherein the third servo is operable byoperating the fifth finger grip a selected number of times, the numberof times the fifth finger grip is operated corresponding to apredetermined speed setting.